|Publication number||US3965455 A|
|Application number||US 05/464,281|
|Publication date||Jun 22, 1976|
|Filing date||Apr 25, 1974|
|Priority date||Apr 25, 1974|
|Publication number||05464281, 464281, US 3965455 A, US 3965455A, US-A-3965455, US3965455 A, US3965455A|
|Inventors||Michael J. Hurwitz|
|Original Assignee||The United States Of America As Represented By The Secretary Of The Navy|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (9), Non-Patent Citations (3), Referenced by (52), Classifications (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The instant invention relates generally to acoustic transducers used in non-destructive materials testing and underseas applications and more particularly to a transducer and reflector combination which stimulates a focused-arc transducer which produces a line-focus sound beam characteristic of focused-arc transducers.
It is well known in the art of acoustical non-destructive testing that it is desirable to use a sharply focused beam of energy. Many methods have been tried including various shaped transducers and other beam focusing methods such as with acoustic lenses and the like, but none was completely satisfactory for a sharply focused beam.
It has been discovered that the radiation from an annular or ring-shaped transducer, which emits a hollow substantially cylindrical beam of energy, may be effectively and sharply focused along a line having great depth of field emanating from the transducer. This line focus has many advantages over a normal point focus, which is at a certain distance from the focusing apparatus.
Producing an annular or ring-shaped transducers is difficult particularly because the very narrow annulus must be made of separate piezo-electric elements that are selected to be matched in output in order to define a good focus of radiated energy and to minimize the effects of differences in the resonant frequency. This limits the acoustic power that may be transmitted and tends to introduce extraneous reasonances in the transducer.
In view of this difficulty it is desirable to be able to simulate a focused arc-shaped transducer with a simple disc transducer and reflectors or or refractors that can operate at high powers and produce a sharp focus over a great depth of field.
Accordingly, an object of the instant invention is to provide a new and improved acoustic transducer for non-destructive materials testing.
Another object of the present invention is to simulate an arc-shaped transducer with a simple disc transducer.
Still another object of the present invention is to provide a beam of acoustic energy capable of being sharply focused along a line emanating from a disc transducer.
A further object of the instant invention is to greatly simplify the construction and improve the performance of a focused arc-shaped transducers which have the property of being in sharp focus at essentially all ranges from the transducer.
Briefly these and other objects of the instant invention are attained by the use of one simple disc transducer radiating acoustic energy into a compound reflector to produce a real image or virtual image of a narrow annular coherent sound source. This arrangement simulates a focused arc-shaped transducer and is superior in performance as well as simplified in construction.
A more complete understanding of the invention and many of the attendant advantages thereof will be readily appreciated as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
FIG. 1 is a cross-sectional view of a simulated focused arc transducer giving a real image; and
FIG. 2 is a cross-sectional view of a simulated focused arc transducer giving a virtual image.
Referring now to the drawings wherein like reference numerals designate corresponding parts throughout the several views, there is shown generally a transducer 10 radiating an acoustic signal to a circular reflector 12, made of stainless steel or the like.
The transducer 10 may be a simple disc or polygon transducer and made of a piezoceramic material. Referring particularly to FIG. 1 the transducer 10 is attached adjacent the open face of the reflector 12 by a plurality of struts 14 to maintain a precise relative orientation. A conical reflector surface 16, formed concentrically in the reflector 12, is shown subjacent to the transducer 10. Radially outward from the conical reflector surface 16, is a concave parabolic reflector surface 18 formed around the reflector 12. Supported by the transducer 10 and the struts 14 a slight distance in front of the reflector 12 is a disc having an annular slot therein thus forming an aperture stop 20 with the slot adjacent the parabolic reflector surface 18.
Referring now to FIG. 2 the transducer 10 is mounted in a central bore 11 of the reflector 12, to radiate outwardly. A conical reflector surface 15 is separate from the reflector 12 but mounted thereto with a plurality of struts 14, and positioned directly in front of the transducer 10. Radially outward from the conical surface 15 is a convex parabolic or partial torus reflector surface 17 formed around the reflector 12.
The operation of the devices of FIG. 1 and FIG. 2 is substantially the same to produce the unique line-focus sound beam shown in both figures. It is to be understood that both the transducer-reflector and the test specimen are normally submerged in water in ultrasonic non-destructive testing. Referring to FIG. 2, in this cross-sectional drawing, plane waves are emitted from the transducer 10, which may be 1 to 2 inches in diameter. These plane waves travel through water to impinge on the conical reflector 15 made of stainless steel or the like. Here the waves reflect and are converted to a radially outward moving cylindrical wave. This cylindrical wave then reflects from the metallic reflector 17, which has the shape of a partial torus and is positioned coaxial with the conical reflector 15. The finally reflected wave is transformed into a wavefront the same as would have been radiated by a ring source at the location shown in FIG. 2 as a "virtual ring source", where the radiated diverging rays would converge behind the reflector 12. As has now become obvious, once it is realized that a plane wave front can be reshaped by the use of compound reflectors to form a focused-arc transducer beam, there are many other embodiments that would perform in the same manner.
FIG. 1 shows another such embodiment wherein the plane wave front from a disc transducer 10 is emitted toward the rear, and impinges on the conical reflector 16 having a half angle approximating 50° from its axis of symmetry to its surface of revolution, or in other words, an included angle of 100°. Here the reflection is an upward and outward moving slightly conical wavefront. This wavefront is then reflected by a parabolic surface of revolution or a paraboloid surface 18 that is positioned coaxial with the conical reflector. This paraboloid reflector is designed to accept the impinging conical wavefront and focus it in a narrow annular aperture 22. The wavefront is therefore transformed into a form such as would be radiated by a ring source at the location shown as the "real ring source" in the aperture 22.
In both embodiments the beam is projected to a sharp line of focus normal to the transducer and having a long depth of field and it is to be understood that the reflectors need not be a complete disc, but rather a segment of a disc would still produce the desired line focus. In fact a segment maybe used for transmitting and a segment for receiving.
Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2228024 *||Feb 1, 1940||Jan 7, 1941||Abrahams Alexander I||Directive acoustic pickup|
|US2342721 *||Oct 10, 1941||Feb 29, 1944||Rudolf Boerner||Parabolic reflector|
|US2370053 *||Dec 31, 1940||Feb 20, 1945||Rca Corp||Directive antenna system|
|US2855526 *||Oct 24, 1955||Oct 7, 1958||Aeroprojects Inc||Apparatus for generating ultrasonic energy of high intensity|
|US3209361 *||Jan 14, 1963||Sep 28, 1965||Webb James E||Cassegrainian antenna subreflector flange for suppressing ground noise|
|US3241147 *||Dec 16, 1963||Mar 15, 1966||Bell Telephone Labor Inc||Antenna utilizing intermediate cuspate reflector to couple energy from feed to main reflector|
|US3262307 *||Oct 28, 1963||Jul 26, 1966||Hart Stephen D||Omnidirectional ultrasonic search system|
|US3325779 *||Sep 13, 1965||Jun 13, 1967||Westinghouse Electric Corp||Transducer|
|US3451260 *||Mar 23, 1966||Jun 24, 1969||Us Health Education & Welfare||Apparatus for ultrasonic scanning using an elliptic reflecting system|
|1||*||"Related Experiments with Sound Waves and Electromagnetic Waves", Kock from Proceedings of the IRE, July 1959, vol. 47, No. 7, pp. 1192-1201.|
|2||"The Journal of the Acoustical Society of America", vol. 21, No. 5, Sept. 49, pp. 471-481, Refracting Sound Waves.|
|3||*||"The Journal of the Acoustical Society of America", vol. 21, No. 5, Sept. 49, pp. 471-481, Refracting Sound Waves.|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4042845 *||Mar 25, 1976||Aug 16, 1977||Sontrix Division Of Pittway Corporation||Transducer assembly and method for radiating and detecting energy over controlled beam width|
|US4044273 *||Nov 25, 1975||Aug 23, 1977||Hitachi, Ltd.||Ultrasonic transducer|
|US4131874 *||May 12, 1977||Dec 26, 1978||Westinghouse Electric Corp.||Inertial balanced dipole hydrophone|
|US4260928 *||Nov 9, 1978||Apr 7, 1981||General Electric Company||Electro-acoustic transducer with horn and reflector|
|US4495817 *||May 25, 1983||Jan 29, 1985||The Ontario Cancer Institute||Ultrasonic imaging device|
|US4530077 *||May 19, 1983||Jul 16, 1985||Xecutek Corporation||Efficient low cost transducer system|
|US4550609 *||Sep 16, 1983||Nov 5, 1985||National Research Development Corp.||Acoustic lens|
|US4791430 *||Jun 12, 1986||Dec 13, 1988||Agtronics Pty. Limited||Ultrasonic antenna|
|US5121340 *||Jun 8, 1990||Jun 9, 1992||Campbell Scientific, Inc.||Multi-level probe and system for measurement of physical conditions in liquid-containing tanks|
|US7167415||Sep 15, 2004||Jan 23, 2007||Packaging Technologies & Inspection Llc||Transducers for focusing sonic energy in transmitting and receiving device|
|US7621369 *||Jun 16, 2006||Nov 24, 2009||Graber Curtis E||Acoustic energy projection system|
|US7766122||Jun 10, 2009||Aug 3, 2010||Graber Curtis E||Acoustic energy projection system|
|US7824348 *||Sep 16, 2004||Nov 2, 2010||Guided Therapy Systems, L.L.C.||System and method for variable depth ultrasound treatment|
|US8166332||Jul 24, 2009||Apr 24, 2012||Ardent Sound, Inc.||Treatment system for enhancing safety of computer peripheral for use with medical devices by isolating host AC power|
|US8235909||May 11, 2005||Aug 7, 2012||Guided Therapy Systems, L.L.C.||Method and system for controlled scanning, imaging and/or therapy|
|US8282554||Oct 9, 2012||Guided Therapy Systems, Llc||Methods for treatment of sweat glands|
|US8333700||Sep 4, 2012||Dec 18, 2012||Guided Therapy Systems, L.L.C.||Methods for treatment of hyperhidrosis|
|US8366622||Apr 11, 2012||Feb 5, 2013||Guided Therapy Systems, Llc||Treatment of sub-dermal regions for cosmetic effects|
|US8409097||Mar 24, 2011||Apr 2, 2013||Ardent Sound, Inc||Visual imaging system for ultrasonic probe|
|US8444562||Jun 12, 2012||May 21, 2013||Guided Therapy Systems, Llc||System and method for treating muscle, tendon, ligament and cartilage tissue|
|US8460193||Jun 3, 2010||Jun 11, 2013||Guided Therapy Systems Llc||System and method for ultra-high frequency ultrasound treatment|
|US8480585||May 4, 2007||Jul 9, 2013||Guided Therapy Systems, Llc||Imaging, therapy and temperature monitoring ultrasonic system and method|
|US8506486||Nov 16, 2012||Aug 13, 2013||Guided Therapy Systems, Llc||Ultrasound treatment of sub-dermal tissue for cosmetic effects|
|US8523775||Sep 4, 2012||Sep 3, 2013||Guided Therapy Systems, Llc||Energy based hyperhidrosis treatment|
|US8535228||Feb 8, 2008||Sep 17, 2013||Guided Therapy Systems, Llc||Method and system for noninvasive face lifts and deep tissue tightening|
|US8636665||Mar 7, 2013||Jan 28, 2014||Guided Therapy Systems, Llc||Method and system for ultrasound treatment of fat|
|US8641622||Sep 12, 2011||Feb 4, 2014||Guided Therapy Systems, Llc||Method and system for treating photoaged tissue|
|US8663112||Dec 23, 2009||Mar 4, 2014||Guided Therapy Systems, Llc||Methods and systems for fat reduction and/or cellulite treatment|
|US8672848||Jan 23, 2012||Mar 18, 2014||Guided Therapy Systems, Llc||Method and system for treating cellulite|
|US8690778||Jun 21, 2013||Apr 8, 2014||Guided Therapy Systems, Llc||Energy-based tissue tightening|
|US8690779||Jun 21, 2013||Apr 8, 2014||Guided Therapy Systems, Llc||Noninvasive aesthetic treatment for tightening tissue|
|US8690780||Jun 21, 2013||Apr 8, 2014||Guided Therapy Systems, Llc||Noninvasive tissue tightening for cosmetic effects|
|US8708935||Jul 12, 2010||Apr 29, 2014||Guided Therapy Systems, Llc||System and method for variable depth ultrasound treatment|
|US8715186||Nov 24, 2010||May 6, 2014||Guided Therapy Systems, Llc||Methods and systems for generating thermal bubbles for improved ultrasound imaging and therapy|
|US8764687||May 7, 2008||Jul 1, 2014||Guided Therapy Systems, Llc||Methods and systems for coupling and focusing acoustic energy using a coupler member|
|US8857438||Nov 8, 2011||Oct 14, 2014||Ulthera, Inc.||Devices and methods for acoustic shielding|
|US8858471 *||Jul 10, 2012||Oct 14, 2014||Guided Therapy Systems, Llc||Methods and systems for ultrasound treatment|
|US8868958||Apr 23, 2012||Oct 21, 2014||Ardent Sound, Inc||Method and system for enhancing computer peripheral safety|
|US8915853||Mar 15, 2013||Dec 23, 2014||Guided Therapy Systems, Llc||Methods for face and neck lifts|
|US8915854||Jan 27, 2014||Dec 23, 2014||Guided Therapy Systems, Llc||Method for fat and cellulite reduction|
|US8915870||Oct 6, 2009||Dec 23, 2014||Guided Therapy Systems, Llc||Method and system for treating stretch marks|
|US8920324||Feb 27, 2014||Dec 30, 2014||Guided Therapy Systems, Llc||Energy based fat reduction|
|US8932224||Jul 25, 2013||Jan 13, 2015||Guided Therapy Systems, Llc||Energy based hyperhidrosis treatment|
|US9011336||May 7, 2008||Apr 21, 2015||Guided Therapy Systems, Llc||Method and system for combined energy therapy profile|
|US9011337||Jul 11, 2012||Apr 21, 2015||Guided Therapy Systems, Llc||Systems and methods for monitoring and controlling ultrasound power output and stability|
|US9039617||May 6, 2014||May 26, 2015||Guided Therapy Systems, Llc||Methods and systems for generating thermal bubbles for improved ultrasound imaging and therapy|
|US9039619||Jan 31, 2014||May 26, 2015||Guided Therapy Systems, L.L.C.||Methods for treating skin laxity|
|US9095697||Aug 13, 2013||Aug 4, 2015||Guided Therapy Systems, Llc||Methods for preheating tissue for cosmetic treatment of the face and body|
|US20050256406 *||May 11, 2005||Nov 17, 2005||Guided Therapy Systems, Inc.||Method and system for controlled scanning, imaging and/or therapy|
|US20130012842 *||Jul 10, 2012||Jan 10, 2013||Guided Therapy Systems, Llc||Methods and systems for ultrasound treatment|
|EP0095383A2 *||May 25, 1983||Nov 30, 1983||Ontario Cancer Institute||Ultrasonic imaging device|
|EP0155028A1 *||Feb 14, 1985||Sep 18, 1985||Dornier Medizintechnik Gmbh||An apparatus for the non-contact disintegration of concrements present in a body|
|U.S. Classification||367/151, 310/335, 343/840|